This invention relates to a valve for controlling the flow rate of hot pitch or other highly viscous fluids, and more particularly to an improved valve rod guide particularly suitable for use in flow control valves of the class just-mentioned.
A problem often encountered in controlling the flow rate of hot pitch at about 300.degree.-400.degree. C is that a rod of a flow regulator valve is seized in the rod guide due to intrusion of hot sticky pitch in the small clearance between the valve rod and the rod guide. This problem cannot be solved simply by increasing the diameter of the center aperture in the rod guide which slidably receives the valve rod.
It is an object of the present invention to provide a pitch flow control valve which will eliminate the above-mentioned problem
It is a more particular object of the invention to provide a pitch flow control valve employing an improved valve rod guide which will preclude seizure of the valve rod due to intruding hot sticky pitch.
It is still another object of the present invention to provide a pitch flow control valve employing an improved valve rod guide which is provided with a center guide aperture having a number of narrow axial ridges around the circumference of the valve rod for linear sliding contact therewith.